Essential Oils of Lavender and Fennel for Inhibiting Tomato Spotted Wilt Virus in Pepper Plants

Commercial batches of pepper fruits, a variety of the long red fleshy pepper with serious deformities were established in the period 2014-2016. Analyses of spotted and deformed fruits purchased from supermarkets in the summer months were carried out by the serological method ELISA, variant DAS-ELISA and artificial inoculation of test (indicator) plants. The studies showed that the deformities in the pepper fruits were caused mainly by Tomato spotted wilt virus (TSWV). The latter is an important viral pathogen of pepper. We tested essential oils from lavender (Lavandula angustifolia Mill.) and fennel (Foeniculum officinale All. var. dulce) by dilutions in concentrations of 1000 ppm, 2000 ppm, 3000 ppm, 5000 ppm and 10000 ppm as a possible means of control against TSWV. The diluted essential oils were mixed with TSWV infectious sap (inoculum) and pepper plants of the variety Sofiyska kapiya were inoculated in each variant. The results showed that lavender essential oil inhibited TSWV in vitro in the pepper plants in the following concentrations: 3000 ppm, 5000 ppm and 10000 ppm. Fennel essential oil did not show an inhibiting effect in any of the five concentrations. The initial results suggested that the studies on lavender essential oil as a possible means with an inhibiting effect against TSWV should be continued by an in vivo trials.